The technical name for the cables that operate mechanical shifters and brakes is ”Bowden cable”.
The way a Bowden cable works is that the sheath/outer cable/casing will push just as hard as the inner cable pulls.
So the basic operation of the brake is that pulling on the lever pinches one end of the brake arms together, causing the other ends to pinch around the rim.

And due to this push/pull symmetry, it doesn’t matter if you shorten the inner wire, or lengthen the casing. Both actions will bring the pad ends of the brake arms closer together.